Final answer:
The atlanto-occipital joint between the first cervical vertebra and the skull contributes the most to sagittal plane mobility, allowing for flexion and extension movements.
Step-by-step explanation:
The cervical spine consists of seven vertebrae, labeled C1 through C7, and it is located in the neck region of the spine. When it comes to sagittal plane mobility, the two primary movements involved are flexion and extension.
The level in the cervical spine that contributes the most to sagittal plane mobility is the atlanto-occipital joint (C0-C1), which is the joint between the atlas (C1) and the occipital bone at the base of the skull. This joint allows for significant flexion and extension of the head and neck.
The primary movements in the sagittal plane at the atlanto-occipital joint include:
Flexion: This movement involves bringing the chin toward the chest, allowing the head to move downward.
Extension: This movement involves tilting the head backward, looking upward.
While the other cervical vertebrae (C2 through C7) also contribute to sagittal plane mobility to some extent, the majority of the range of motion occurs at the atlanto-occipital joint. The intervertebral joints between the other cervical vertebrae allow for smaller degrees of flexion and extension, and the cumulative effect of these motions contributes to the overall mobility of the cervical spine in the sagittal plane.